<?php

/**
 * @file CAS/PGTStorage/pgt-file.php
 * Basic class for PGT file storage
 */

/**
 * @class PGTStorageFile
 * The PGTStorageFile class is a class for PGT file storage. An instance of
 * this class is returned by CASClient::SetPGTStorageFile().
 *
 * @author Pascal Aubry <pascal.aubry at univ-rennes1.fr>
 *
 * @ingroup internalPGTStorageFile
 */

class PGTStorageFile extends PGTStorage
{
    /**
     * @addtogroup internalPGTStorageFile
     * @{
     */

    /**
     * a string telling where PGT's should be stored on the filesystem. Written by
     * PGTStorageFile::PGTStorageFile(), read by getPath().
     *
     * @private
     */
    var $_path;

    /**
     * This method returns the name of the directory where PGT's should be stored
     * on the filesystem.
     *
     * @return the name of a directory (with leading and trailing '/')
     *
     * @private
     */
    function getPath()
    {
        return $this->_path;
    }

    /**
     * a string telling the format to use to store PGT's (plain or xml). Written by
     * PGTStorageFile::PGTStorageFile(), read by getFormat().
     *
     * @private
     */
    var $_format;

    /**
     * This method returns the format to use when storing PGT's on the filesystem.
     *
     * @return a string corresponding to the format used (plain or xml).
     *
     * @private
     */
    function getFormat()
    {
        return $this->_format;
    }

    // ########################################################################
    //  DEBUGGING
    // ########################################################################

    /**
     * This method returns an informational string giving the type of storage
     * used by the object (used for debugging purposes).
     *
     * @return an informational string.
     * @public
     */
    function getStorageType()
    {
        return "file";
    }

    /**
     * This method returns an informational string giving informations on the
     * parameters of the storage.(used for debugging purposes).
     *
     * @return an informational string.
     * @public
     */
    function getStorageInfo()
    {
        return 'path=`'.$this->getPath().'\', format=`'.$this->getFormat().'\'';
    }

    // ########################################################################
    //  CONSTRUCTOR
    // ########################################################################

    /**
     * The class constructor, called by CASClient::SetPGTStorageFile().
     *
     * @param $cas_parent the CASClient instance that creates the object.
     * @param $format the format used to store the PGT's (`plain' and `xml' allowed).
     * @param $path the path where the PGT's should be stored
     *
     * @public
     */
    function PGTStorageFile($cas_parent,$format,$path)
    {
        phpCAS::traceBegin();
        // call the ancestor's constructor
        $this->PGTStorage($cas_parent);

        if (empty($format) ) $format = CAS_PGT_STORAGE_FILE_DEFAULT_FORMAT;
        if (empty($path) ) $path = CAS_PGT_STORAGE_FILE_DEFAULT_PATH;

        // check that the path is an absolute path
        if (getenv("OS")=="Windows_NT"){

            if (!preg_match('`^[a-zA-Z]:`', $path)) {
                phpCAS::error('an absolute path is needed for PGT storage to file');
            }

        }
        else
        {

            if ( $path[0] != '/' ) {
                phpCAS::error('an absolute path is needed for PGT storage to file');
            }

            // store the path (with a leading and trailing '/')
            $path = preg_replace('|[/]*$|','/',$path);
            $path = preg_replace('|^[/]*|','/',$path);
        }

        $this->_path = $path;
        // check the format and store it
        switch ($format) {
            case CAS_PGT_STORAGE_FILE_FORMAT_PLAIN:
            case CAS_PGT_STORAGE_FILE_FORMAT_XML:
                $this->_format = $format;
                break;
            default:
                phpCAS::error('unknown PGT file storage format (`'.CAS_PGT_STORAGE_FILE_FORMAT_PLAIN.'\' and `'.CAS_PGT_STORAGE_FILE_FORMAT_XML.'\' allowed)');
        }
        phpCAS::traceEnd();
    }

    // ########################################################################
    //  INITIALIZATION
    // ########################################################################

    /**
     * This method is used to initialize the storage. Halts on error.
     *
     * @public
     */
    function init()
    {
        phpCAS::traceBegin();
        // if the storage has already been initialized, return immediatly
        if ( $this->isInitialized() )
        return;
        // call the ancestor's method (mark as initialized)
        parent::init();
        phpCAS::traceEnd();
    }

    // ########################################################################
    //  PGT I/O
    // ########################################################################

    /**
     * This method returns the filename corresponding to a PGT Iou.
     *
     * @param $pgt_iou the PGT iou.
     *
     * @return a filename
     * @private
     */
    function getPGTIouFilename($pgt_iou)
    {
        phpCAS::traceBegin();
        $filename = $this->getPath().$pgt_iou.'.'.$this->getFormat();
        phpCAS::traceEnd($filename);
        return $filename;
    }

    /**
     * This method stores a PGT and its corresponding PGT Iou into a file. Echoes a
     * warning on error.
     *
     * @param $pgt the PGT
     * @param $pgt_iou the PGT iou
     *
     * @public
     */
    function write($pgt,$pgt_iou)
    {
        phpCAS::traceBegin();
        $fname = $this->getPGTIouFilename($pgt_iou);
        if ( $f=fopen($fname,"w") ) {
            if ( fputs($f,$pgt) === FALSE ) {
                phpCAS::error('could not write PGT to `'.$fname.'\'');
            }
            fclose($f);
        } else {
            phpCAS::error('could not open `'.$fname.'\'');
        }
        phpCAS::traceEnd();
    }

    /**
     * This method reads a PGT corresponding to a PGT Iou and deletes the
     * corresponding file.
     *
     * @param $pgt_iou the PGT iou
     *
     * @return the corresponding PGT, or FALSE on error
     *
     * @public
     */
    function read($pgt_iou)
    {
        phpCAS::traceBegin();
        $pgt = FALSE;
        $fname = $this->getPGTIouFilename($pgt_iou);
        if ( !($f=fopen($fname,"r")) ) {
            phpCAS::trace('could not open `'.$fname.'\'');
        } else {
            if ( ($pgt=fgets($f)) === FALSE ) {
                phpCAS::trace('could not read PGT from `'.$fname.'\'');
            }
            fclose($f);
        }

        // delete the PGT file
        @unlink($fname);

        phpCAS::traceEnd($pgt);
        return $pgt;
    }

    /** @} */

}


?>